1. Field of the Invention
The present invention relates generally to a high-speed scanning arrangement, and particularly although not exclusively to such a scanning arrangement for use in hand-held or fixed optical scanners such as bar code scanners. In one embodiment the invention relates to a bar code reader with an integrated scanning component module mountable on a printed circuit board.
2. Description of the Related Art
Various optical readers and optical scanners have been developed heretofore to optically read bar code symbols applied to objects in order to identify the object by optically reading the symbol thereon. The bar code symbol itself is a coded pattern comprised of a series of bars of various widths and spaced apart from one another to bound spaces of various widths, the bars and spaces having different light reflecting properties. The readers and scanners electro-optically decoded the coded patterns to multiple digit representations descriptive of the objects. Scanners of this general type have been disclosed, for example, in U.S. Pat. Nos. 4,251,798; 4,360,798; 4,369,361; 4,387,297; 4,593,186; 4,496,831; 4,409,470; 4,808,804; 4,816,661; 4,816,660; and 4,871,904, all of said patents having been assigned to the same assignee as the instant invention and being hereby incorporated herein by reference.
As disclosed in the above-identified patents and applications, a particularly advantageous embodiment of such a scanner resided, inter alia, in emitting a light beam, preferably a laser beam, emitted from a light source, preferably a gas laser or a laser diode, and in directing the laser beam to a symbol to be read. En route to the symbol, the laser beam was directed to, and reflected off, a light reflector of a scanning component. The scanning component moved the reflector in a cyclical fashion and caused the laser beam to repetitively scan the symbol. The symbol reflected the laser beam incident thereon. A portion of the incident light reflected off the symbol was collected and detected by a detector component, e.g. a photodiode, of the scanner. The photodiode had a field of view, and the detected light over the field of view was decoded by electrical decode circuitry into data desciprive of the symbol for subsequent processing. The cyclically movable reflector swept the laser beam across the symbol and/or swept the field of view during scanning.
U.S. Pat. Nos. 4,387,297 and 4,496,831 disclose a high speed scanning component including an electric motor operative for reciprocatingly oscillating a reflector in opposite circumferential directions relative to an output shaft of the motor. Electrical power is continuously applied to the motor during scanning. The light beam which impinges on the light reflector is rapidly swept across a symbol to be scanned in a predetermined cyclical manner. The scanning component comprises at least one scan means for sweeping the symbol along a predetermined direction (X-axis) lengthwise thereof. The scanning component may also comprise another scan means for sweeping the symbol along a transverse direction (Y-axis) which is substantially orthogonal to the predetermined direction, to thereby generate a raster-type scan pattern over the symbol. In addition to a single scan line and the raster-type pattern, other types of scan patterns are also possible, such as, x-shaped, Lissajous, curvilinear (see U.S. Pat. No. 4,871,904), etc. For example, if the X and Y axis scanning motors are both driven such that the light reflectors are driven at a sinusoidally-varying rate of speed, then the scan pattern at the reference plant will be a Lissajous-type pattern for omni-directional scanning of the symbols. The use of two separate scanning motors and control means to produce the multi-axis and omni-directional scanning pattern increases material and labor costs as well as the amount of electrical power needed to operate the scanner. In addition, the relatively complicated motor shaft and bearing arrangements of the scanning components may result in a useful life that is inadequate for some applications.
European patent application 456,095 also discloses various prior art types of high speed scanning arrangements, as do U.S. Pat. Nos. 5,280,165 and 5,367,151.
It is a general object of the present invention to enhance the state-of-the-art of high speed scanning arrangements, and particularly although not exclusively for such arrangements for use in optical scanners for reading indicia of differing light reflectivity, particularly laser scanners for reading bar code symbols.
A further object of the present invention is to provide an inexpensive, robust and easily replaceable scanning arrangement.
Yet another object of the invention is to increase the working lifetime of the scanning components.
Yet another object is to provide a robust, low cost, hand-held optical scanner.
Yet a further object is to provide a means for determining when a scanner has been exposed to high levels of mechanical shock.
Yet a further object is to attempt to alleviate high levels of mechanical shock.
According to one aspect of the invention, there is provided an optical scanning assembly including an optics module having an optical scanner and an optical detector for detecting light reflected from an indicia being read and for providing data signals representative thereof, and a printed circuit board (PCB) carrying electrical circuitry for controlling said optics module. A first electrical connector jointly movable with the optics module mates with a second electrical connector fixed to the PCB for electrically coupling the optics module and the PCB.
The electrical connectors may supply both power and control signals to the optics module, and may also operate to transfer the data signals from the optics module to the PCB. T he electrical connection is conveniently of the plug-in type (for example, it maybe PCMCIA-compatible). In preferred embodiments, the electrical connectors act to mount the optics module on the PCB. Alternatively, the module may be otherwise secured to the PCB, with the electrical connectors acting simply to transfer power and/or data.
According to a further aspect of the present invention, there is provided a hand-held electronic device including an abuse-detector for determining when said device has been exposed to mechanical shock above a predetermined design limit.
The abuse-detector may conveniently be secured, for example by means of an adhesive, to a PCB of the electronic device. Preferred electronic devices include all types of portable and/or hand-held electronic equipment, including portable computer terminals, data entry devices, bar code readers, digital cameras and so on.
According to yet a further aspect of the present invention there is provided a hand-held electronic device including an accelerometer for determining when said device is exposed to acceleration above a predetermined limit and for producing a signal representative thereof, and a CPU for running an applications program, said CPU being arranged to shut down said applications program and to store related status information when said signal is received from said accelerometer.
The invention further extends to a method of determining when a hand-held electronic device is exposed to acceleration above a predetermined limit. Such a method preferably includes the step of producing a signal representative thereof, and closing down any active applications programs and storing related status information.
When it is determined that the device is being exposed to an acceleration above a predetermined limit, the CPU may enter a power-down mode. In addition, one or more mechanical protection devices may operate to prevent mechanical damage from the expected resultant shock. For example, mechanical protection may be applied, by means of a mechanical lock, shock absorbers, or the like, to prevent mechanical damage to the heads and/or platters of a disk drive.
In yet a further aspect of the invention there is provided a hand-held electronic device including an accelerometer having an accelerometer output, a deceleration-level detector for determining from said accelerometer output when said device has been exposed to a deceleration above a given value, and a store for storing for later analysis values representative of the accelerometer output for a time period prior to the deceleration-level detector determining that the device has been so exposed.
In yet another aspect there is provided a method of operating a hand-held electronic device, said device including an accelerometer having an accelerometer output and a store, the method comprising:
(a) Monitoring said accelerometer output, and determining when said device has been exposed to a deceleration greater than a given value; and
(b) Storing in the store, for later analysis, values representative of the accelerometer output for a time period prior to the said determination.
Preferably, the accelerometer output is filtered or smoothed, before being applied to the deceleration-level detector. Means may then be provided, for example, a signal comparator, for determining when the deceleration level is sufficiently high. Once such a determination has been made, the prior output of the accelerometer (for example over the preceding five or ten seconds) is stored in memory for future analysis. Conveniently, an AID converter is also provided, sampling the signal at sufficiently frequent intervals that future analysis may be carried out on the discrete digitized and stored values.
Separate x, y and z accelerometers may be provided, supplying respectively acceleration outputs in the x, y and z directions. Each output may be separately filtered and compared with a given acceleration level, thereby allowing separate triggering in each of the x, y and z channels. In addition, a separate channel may be provided for other status information, such as for example temperature information, on/off status information for the electronic device and so on. A further store may be provided for storing such information in the event that a deceleration is detected of a fixed limit.